Dental caries are associated with the bacterial contained in dental biofilm. Dental biofilm is complex, with a well-organized structure. Up to 500 bacterial species have been identified in dental biofilm. For oral and systemic health, the dental biofilm needs to be regularly and meticulously removed. Removal and reduction of biofilm can be by mechanical means or mechanical and chemical means. There have been increasing efforts to inhibit the development of biofilm. It is known prior to the development of dental biofilm, the salivary or acquired pellicle forms. This occurs through the adsorption of protein from saliva onto the clean tooth surface. Acquired pellicle formation provides oral bacterial with biding sites, resulting in bacterial adhesion, the first step in the formation of dental biofilm. Therefore, surface modification should inhibit the development of the acquired pellicle and dental biofilm.
In restorative dentistry, secondary caries are well known, which often occurs at the interface between the restoration and the cavity preparation as a result of demineralization of tooth structure due to the dental plaque formation by acid-producing bacteria such as Streptococcus mutans (S. mutans) in presence of fermentable carbohydrates. Thus dental compositions with antibacterial/antimicrobial effect were formulated by incorporation of a variety of antibacterial/antimicrobial agents, such as chlorhexidine, silver ions, and fluoride. Although such low molecular organic compounds demonstrated immediate effectiveness, there are issues related to their long-term effectiveness, potential toxicity and impact to the mechanical strength of the formulated dental composition due to the leachability. On the other hand, solid antibacterial/antimicrobial agents such as silver nanoparticles and polymeric QAS nanoparticles were also developed to address those issues associated with the low molecular weight of antibacterial/antimicrobial agents. There are issues like color stability and optical opacity and mechanical strength. Recently polymerizable antibacterial/antimicrobial resins were developed but their effectiveness varied and most of them demonstrated negative impact on mechanical property of the formulated dental composition.
U.S. Pat. No. 5,494,987 disclosed antimicrobial polymerizable compositions having an ethylenically unsaturated monomer with antimicrobial activity for dental application composed of quaternary ammonium dodecylpyridinium (MDPB).
U.S. Publication No. 2010/0256242 disclosed a polymerizable biomedical composition that includes a quaternary ammonium group bonded at its quaternary sites.
U.S. Pat. Nos. 6,710,181 and 7,094,845 disclosed an imidazole-based silane and monocarboxylic acid salt for improving adhesion between resins and metal or glass.
U.S. Pat. No. 7,553,881 disclosed dental compositions based on polymerizable macromers based on quaternary ammonium salts for antimicrobial effect.
Thus there is strong need to highly effective polymerizable antibacterial resin that is capable to offer a balanced antibacterial effectiveness and excellent mechanical property without severe cytotoxicity. In this invention, a method and composition of polymerizable antibacterial/antimicrobial resins is disclosed and high performance dental compositions are formulated from such novel bioactive resins.